diff --git a/bin/pt-index-usage b/bin/pt-index-usage
index 3bcd562d2..ed296d4c1 100755
--- a/bin/pt-index-usage
+++ b/bin/pt-index-usage
@@ -3029,6 +3029,10 @@ sub parse_event {
       }
 
       PTDEBUG && _d('Properties of event:', Dumper(\@properties));
+      if ( @properties % 2 ) {
+         PTDEBUG && _d('Skipping malformed event (odd properties):', Dumper(\@properties));
+         next EVENT;
+      }
       my $event = { @properties };
       if ( !$event->{arg} ) {
          PTDEBUG && _d('Partial event, no arg');
diff --git a/bin/pt-query-digest b/bin/pt-query-digest
index abeb8c94b..d0a20a467 100755
--- a/bin/pt-query-digest
+++ b/bin/pt-query-digest
@@ -5234,6 +5234,10 @@ sub parse_event {
       }
 
       PTDEBUG && _d('Properties of event:', Dumper(\@properties));
+      if ( @properties % 2 ) {
+         PTDEBUG && _d('Skipping malformed event (odd properties):', Dumper(\@properties));
+         next EVENT;
+      }
       my $event = { @properties };
       if ( !$event->{arg} ) {
          PTDEBUG && _d('Partial event, no arg');
@@ -5625,6 +5629,10 @@ sub make_handler {
       );
    }
 
+   if ( $type =~ m/^(?:num|bool)$/ ) {
+      push @lines, q{$val = 0 if defined $val && $val eq '';};
+   }
+
    if ( $type eq 'num' && $self->{attrib_limit} ) {
       push @lines, (
          "if ( \$val > $self->{attrib_limit} ) {",
@@ -5654,7 +5662,7 @@ sub make_handler {
          . $gt . ' PLACE->{max};',
       );
       if ( $track{sum} ) {
-         push @tmp, 'PLACE->{sum} += $val;';
+         push @tmp, 'PLACE->{sum} += (defined $val && $val ne q{} ? $val : 0);';
       }
 
       if ( $track{all} ) {
diff --git a/bin/pt-table-usage b/bin/pt-table-usage
index a3882f876..86d7fcc9d 100755
--- a/bin/pt-table-usage
+++ b/bin/pt-table-usage
@@ -2451,6 +2451,10 @@ sub parse_event {
       }
 
       PTDEBUG && _d('Properties of event:', Dumper(\@properties));
+      if ( @properties % 2 ) {
+         PTDEBUG && _d('Skipping malformed event (odd properties):', Dumper(\@properties));
+         next EVENT;
+      }
       my $event = { @properties };
       if ( !$event->{arg} ) {
          PTDEBUG && _d('Partial event, no arg');
diff --git a/bin/pt-upgrade b/bin/pt-upgrade
index dc69194a7..825d189ff 100755
--- a/bin/pt-upgrade
+++ b/bin/pt-upgrade
@@ -6995,6 +6995,10 @@ sub parse_event {
       }
 
       PTDEBUG && _d('Properties of event:', Dumper(\@properties));
+      if ( @properties % 2 ) {
+         PTDEBUG && _d('Skipping malformed event (odd properties):', Dumper(\@properties));
+         next EVENT;
+      }
       my $event = { @properties };
       if ( !$event->{arg} ) {
          PTDEBUG && _d('Partial event, no arg');
diff --git a/lib/EventAggregator.pm b/lib/EventAggregator.pm
index 05624304e..728069ef9 100644
--- a/lib/EventAggregator.pm
+++ b/lib/EventAggregator.pm
@@ -380,6 +380,12 @@ sub make_handler {
       );
    }
 
+   # Slow log and similar sources can leave numeric attributes as ''; treat as 0
+   # so type detection and later arithmetic stay consistent.
+   if ( $type =~ m/^(?:num|bool)$/ ) {
+      push @lines, q{$val = 0 if defined $val && $val eq '';};
+   }
+
    # Make sure the value is constrained to legal limits.  If it's out of
    # bounds, just use the last-seen value for it.
    if ( $type eq 'num' && $self->{attrib_limit} ) {
@@ -422,8 +428,9 @@ sub make_handler {
          'PLACE->{max} = $val if !defined PLACE->{max} || $val '
          . $gt . ' PLACE->{max};',
       );
+      # Num/bool sums must not use += on undef or '' (would warn or incorrectly sum).
       if ( $track{sum} ) {
-         push @tmp, 'PLACE->{sum} += $val;';
+         push @tmp, 'PLACE->{sum} += (defined $val && $val ne q{} ? $val : 0);';
       }
 
       # Save all values in a bucketed list.  See bucket_idx() below.
diff --git a/lib/SlowLogParser.pm b/lib/SlowLogParser.pm
index fa35f587f..6c81ac196 100644
--- a/lib/SlowLogParser.pm
+++ b/lib/SlowLogParser.pm
@@ -309,6 +309,12 @@ sub parse_event {
       # Don't dump $event; want to see full dump of all properties, and after
       # it's been cast into a hash, duplicated keys will be gone.
       PTDEBUG && _d('Properties of event:', Dumper(\@properties));
+      # An odd-length @properties list would pair keys/values wrong in the
+      # hash below; skip the event rather than corrupt aggregation.
+      if ( @properties % 2 ) {
+         PTDEBUG && _d('Skipping malformed event (odd properties):', Dumper(\@properties));
+         next EVENT;
+      }
       my $event = { @properties };
       if ( !$event->{arg} ) {
          PTDEBUG && _d('Partial event, no arg');